In information processing apparatuses, such as computers and servers, and communication devices, such as repeaters and exchanges, a trend toward increases in integration density and performance of electronic equipment and electronic components incorporated therein causes an increased amount of heat to generate and thus power consumption for cooling and emitting waste heat to increase. Methods are known that cool the inside of a housing and emit waste heat therefrom with cooling fans installed near heat sources such as a central processing unit (CPU) and a graphic processing unit (GPU) or a case fan that takes in cooling air from the outside of the housing to generate airflows in a housing.
Some of the former methods are applied to a blade server that can contain multiple blades, each of which includes a CPU, a power supply device, an input/output device, and a cooling fan integrated into one narrow-box unit. The blades, each of which can operate as one server, generate heat dependent on each blade in the blade server. For this reason, a cooling fan is provided in each blade depending on the load thereon, and the fans are individually controlled to properly cool the inside of the housing.
Such a method, disadvantageously, needs a larger number of controlled cooling fans with the increase in the number of blades, often resulting in louder noise, a complicated configuration of an apparatus, and increased costs. On the other hand, the latter methods, which distribute the cooling air introduced by case fans around a housing, can solve such a problem.
Some of the latter methods are applied to a tower-model or rack-mount server, the housing of which contains a plurality of electronic circuit packages. For example, a case fan takes in air from the outside of a housing and the air is blown to each electronic circuit package through a duct provided in the housing. Furthermore, a guide member for adjusting the flow rate is disposed in the flow passage of air, and each electronic circuit package is cooled by an airflow volume dependent on the heat.